One of the weird things about pain is that no-one knows if you’re faking. To date there hasn’t been a test that can tell whether you’re really in pain, or just faking it. Well, that’s about to change according to researchers in Israel and Canada.
While there have been a whole range of approaches to checking out faking such as facial expression, responses to questionnaires, physical testing and physical examinations, none of these have been without serious criticism. And the implications are pretty important to the person being tested – if you’re sincere, but someone says you’re not, how on earth do you prove that you’re really in pain? For clinicians, the problem is very troubling because allegations of faking can strain a working relationship with a person, and hardly lead to a sense of trust. Yet insurance companies routinely ask clinicians to make determinations about fraudulent access to insurance money – and worst of all, clinicians often feel they have little choice other than to participate.
In this study by Kucyi, Sheinman and Defrin, three hypotheses were tested: 1) Whether feigned performance could be detected using warmth and pain threshold measurements; 2) whether there were changes in the statistical properties of performance when participants were faking; and 3) whether an “interference” or distractor presented during testing interferes with the ability to fake and therefore provide a clue to when someone is being sincere or not.
Using university students (I hope they got course credits for participating!) who were not health science students, and were otherwise healthy, the investigators gave very little information about the procedure or hypotheses to minimise expectancy bias. Participants were then tested using a thermal stimulator to obtain “warmth sensation threshold” and “heat-pain thresholds” – this is a form of quantitative sensory testing (QST). TENS was used as a distractor in the experimental case, applied for 2 minutes before measuring the pain threshold, and during the heat pain threshold test. This was repeated with first the threshold test, then TENS. Participants were asked to pretend they were in an insurance office, being tested to establish whether they were experiencing genuine pain, after being told the test would be able to tell whether their pain was real.
What did they find out?
Well in situation one, where both threshold and warmth detection were used, and participants were asked to fake the pain intensity, respondents gave higher warmth detection ratings than normal. Not only this, but the ability to repeat the same response with the same temperature was poorer. Heat pain threshold was also consistently different between the sincere and faked conditions, with heat pain threshold lower when people were faking (to around 3 degrees).
When the second testing option was carried out (using TENS to distract), heat pain threshold was significant lower when participants were faking, and the variance of the feigned + interference condition was three times that of the sincere condition, and the CV of the feigned + interference condition was twice that of the sincere condition.
What does this mean?
Well first of all, it means there are some consistent effects of faking in response to tests of warmth and heat-pain threshold when a distractor like TENS is used. Increased reports of warmth threshold and reduced heat pain threshold were observed, and where statistically significant. Interestingly, it was only when a distractor was used that the variability of reports were found – these authors suggest that people are pretty skilled at giving consistent reports when they’re not being distracted by an additional sensory stimulus.
Now here’s where I begin to pull this apart from a clinical and practical perspective. The authors, to give them credit, indicate that the research is both new and that it may identify some people who do have pain as malingerers. My concerns are that people with chronic pain may not look at all like healthy young university students.
We know very little about the responses to QST by people with different forms of chronic pain. We already know that people with impaired descending noxious inhibitory control respond differently to some forms of QST. We also know that contextual factors including motivation can influence how nervous systems respond to input. But my concerns are far more about the potential harm to those who are tested and found to be malingering when they’re not.
What do you do if you think a person is faking? How do you deal with this? What good does it do to suggest to someone their pain is not real, or isn’t nearly as bad as they make out? Once the words are out of your mouth (or written in a report) any chance of a therapeutic relationship has just flown right out the door. And you’re still left with a person who says they’re having trouble – but now you have an angry, resentful person who has a strong need to prove that they DO have pain.
You see, I think it might be more fruitful to ask why is this person faking pain? If it’s simply for money, surely there are far easier ways to get money than pretending to be disabled by pain? If it’s the case that a person is off out fishing or playing golf or living it up when “supposed” to be in pain, wouldn’t it make more sense to reframe their response as either recovering well (doing what’s healthy) and therefore get on with returning to work; or use a private investigator to demonstrate that he or she is actually capable of doing more than they indicate?
The presence or absence of pain is not really the problem, IMHO. To me we need to address the degree of disability that’s being attributed to pain and work on that. Maybe a greater focus on reducing disability rather than on expensive procedures to remove pain or otherwise get rid of pain is in order?
Kucyi, A., Sheinman, A., Defrin, R. (in press). Distinguishing feigned from sincere performance in psychophysical pain testing. The Journal of Pain.